In women, chemotherapy and radiotherapy can be harmful to the ovaries, causing loss of endocrine and reproductive functions. When gonadotoxic treatment cannot be delayed, ovarian tissue cryobanking is the only way of preserving fertility. This technique, however, is not advisable for patients with certain types of cancer, because of the risk of reintroducing malignant cells present in the cryopreserved tissue. Our objective is therefore to develop a transplantable artificial ovary. To this end, cryopreserved human preantral follicles were isolated and embedded in fibrin formulations prepared with 50 mg/ml fibrinogen and 10 IU/ml thrombin supplemented or not with 3% hyaluronic acid, and respectively xenografted to specially created right and left peritoneal pockets in eight nude mice.